Blood Born
by MizJoely
Summary: "Vampires that couldn't control their bloodlust are to blame," Molly argued. "They're the ones who didn't care if they killed the humans they fed from or not. They're the ones who didn't notice when those humans didn't stay dead." A Sherlolly Vamplock/Zombie Apocalypse mashup.
1. Into Darkness

**Part One: Into Darkness**

 _A/N: Yes, yes, I have x WiPs out there waiting to be updated, but this story is almost completely finished, so here is part one. Rated T for blood and gore - but what do you expect from a vampire-zombie apocalypse fict?_

 _Credit to mel-loves-all for the inspiration, and to lilsherlockian1975 for reading it over. You guys rock, and so do you, my loyal readers!_

 _The story is also posted on AO3 as part of the 2017 Halloween at 221B collection, just FYI. :)_

* * *

The irony was that the vampires had brought it down on themselves. Even him, in his own way, by not grasping the scope of the problem until it was too late for him to do anything to stop it.

He couldn't stop the guilt gnawing at him no matter how many times he reminded himself that he'd always been careful, never Turning any humans if he could avoid it. Not after what he'd seen happen with Eurus and Victor, not after what Moriarty had done to John…

Painful memories, long since believed deleted from his mental hard drive, fought their way into the forefront of his mind, and he spent several precious minutes wrestling them back into oblivion.

For now. They'd always be lurking in the background of his thoughts now that he knew he'd been unsuccessful in fully erasing them.

Once he'd managed to escape from this unwelcome derailment to his train of thought, he immediately returned to the equally unwelcome musings that had plagued him this evening: the irony of vampires being the cause of a zombie apocalypse. Who could have predicted that changing vampire and human genetics over the centuries would give rise to such a nightmare?

Molly Hooper, that's who. One of the very few who'd accurately predicted the disaster that had befallen them.

The human woman he'd forsworn his own kind to protect.

The woman he lo…

No. He could never allow himself to admit to such sentiment. If anyone was unworthy of a human's heart - of _her_ heart - it was a vampire.

Even one who was desperately seeking a way to cure or reverse what his own kind had brought about.

"Penny for your thoughts?"

He had no need to school his expression; centuries of existence had perfected his poker face, erased all evidence in the form of micro-expressions and tics and tells. But his silence, he knew, was eloquent, and Molly had always been far more perceptive than he'd been comfortable with. "Just brooding, as you'd put it," he replied, keeping his tone light. "Weight of the world and all that."

She nodded and rested her head on his shoulder, a comfort meant for both of them, so welcome where once he would have rejected the gesture. "Ah, I see," she replied, just as lightly. "'Vampires are to blame, I'm a vampire, therefore I'm to blame'. The usual association fallacy."

"It's not an association fallacy," he protested as he always did when she tried to ease his personal sense of guilt. "It's a simple fact. Vampires got careless and complacent; biology evolved as it tends to do; vampires failed to take note of that fact - myself included - and zombies came into existence."

"Vampires that couldn't control their bloodlust are to blame," Molly argued back, shivering a bit in the cool night air despite being nearly engulfed in the warm Belstaff he'd scrounged for her. Automatically he placed an arm around her, although his own much cooler body temperature wasn't likely to do much to warm her up. "They're the ones who didn't care if they killed the humans they fed from or not. They're the ones who didn't notice when those humans didn't stay dead. They're the ones who killed so many people in such a short period of time that the contamination spread too quickly to contain-"

"While the rest of us paid no attention until it was almost too late," Sherlock rebutted. He'd been so caught up in his life as a 'consulting detective' that he'd given no heed to the whispers from the vampire community - very few of whom resided in London, his family's ancestral hunting grounds - until after John had been…

 _No. Don't go there. That way lay madness._

"Humans weren't exactly on top of things either," Molly argued back. "Look how our former leaders tried to use it against vampires, to weaponize it, instead of focusing on finding a cure. Talk about shortsightedness!" She snorted inelegantly, and he repressed the urge to smile. He should be annoyed with her for retreading old ground, but instead he was comforted by her attempts to comfort him. After all he'd put her through, she still put him first.

If only he could continue to fool himself into believing that her hero-worship was what he enjoyed most about spending time with her, he'd be much more content. Not happier, but far less concerned about the fate of the world than he currently was. "Either way, it brought about the end of the world as we know it, a world where both humans and vampires are in danger of extinction." He made a discontented growl deep in his throat, the vampire equivalent of a huffing out a breath. "Maybe we should just let nature take its course."

" _But if one man can stand tall, there must be hope for us all, somewhere in the spirit of man_ ," Molly sang softly.

"The War of the Worlds musical, Jeff Wayne, the ghastly bit with the parson and his wife," Sherlock replied automatically, no longer appalled by the way her taste in music had crept into his awareness to the point that he could accurately identify over 85% of her quotes.

What still bemused him, however, was her unflagging ability to find hope in such a hopeless situation. She had no research facilities, no resources aside from him and whatever they could scrounge up in the ruins of London, no knowledge of the fate of most of her friends and family...and yet she sang about the spirit of man with unshakable faith that somehow such a thing was all they needed to set things right again.

Naive. She was hopelessly naive, foolish in those beliefs. He should tell her so - should have told her so years ago, when this all began.

But he never had, and he never would.

 _Sod it,_ he thought suddenly. Forget _keeping an emotional distance_ and _doing what's right_ and pretending all he wanted was friendship and company. The end times had come; if now wasn't the time for him to admit how he felt about her, then it would have to be never.

And he didn't _want_ it to be never.

Resolved, he turned to face her. She tilted her head up inquiringly, her breath catching as he moved his face down to meet hers. Their lips a hair's breadth apart, he murmured, "If not for you, Molly Hooper, I would have allowed myself to starve to death, or jumped off a building so tall even a vampire couldn't survive the fall." Slowly he reached up and stroked his fingers down her cheek. "Molly Hooper, I lo…"

The snap of a twig was all the warning they had; if not for his enhanced hearing, the creature would have been upon them before they could scramble to their feet, and Molly might very well be dead.

Sherlock shoved her away from him, not bothering with a verbal warning, trusting she'd understand once she recognized the danger. He jumped to his feet and rushed the creature, knocking it to the ground and wrapping one hand round its throat while he groped for his machete with the other.

He avoided its snapping teeth and flailing limbs with ease, dispatching it swiftly with one blow of the machete before jumping back to his feet, eyeing the twice-dead corpse with clinical interest. A woman, of mixed Euro-Asian descent, probably in her early twenties when she was infected, undead at least a year judging by the rate of decomp and the condition of her tattered clothing...

"Sh-sherlock?"

He froze at the sound of Molly's voice, only briefly, barely long enough for a human mind to register, although it felt like a lifetime before he made himself turn and look at her.

 _No._

How had he missed it, the second zombie, the one that Molly had managed to dispatch with her hunting knife - now lodged in its forehead, oozing viscous black blood, mouth still agape, teeth...teeth reddened and stained, gobbets of fresh flesh between the teeth and on the lips and...Oh. _God_.

 _NO._


	2. The Enemy Within

_A/N: Thanks to nocturnias and mellovesall, this chapter is ready to go. And surprise! There will be one more chapter after this one, but chapter 3 will definitely be the end. Thank you for all your reviews and for reading this dark little fic. This chapter has blood and gore and stuff, so be aware._

* * *

Blood. There was blood seeping from her right shoulder. She'd pressed her hand against it in an attempt to staunch the bleeding, and her eyes were very wide and very dark against the shocky-white pallor of her skin. "I didn't see it, I should have been watching, we know they tend to travel in groups," she said in a small voice. "But instead I was watching you, making sure you would be all right - and that's silly, you know?" Her voice rose a bit and he recognized the hysteria attempting to overwhelm the shock. "You're a vampire, you can move at blinding speeds even when you're weak because you won't drink more blood from me, and even if it bit you, we know that the bite wouldn't do anything to you. Silly, stupid, but I was worried…"

He moved, finally, pulling her close as he whipped the dark blue scarf from his throat and pressed it to the wound. "Not silly or stupid, just sentiment," he replied, keeping his tone crisp and impartial. "My brother always said it would get me killed one day and look at that, it has."

Molly's brow furrowed in anger; good, it would help combat both the shock and hysteria. "It's not killing _you_ , it's killing _me_ ," she snapped with a futile attempt to push him away. "And your brother was an arse."

"Not gonna argue that point," Sherlock replied, scooping her into his arms before she could protest. "Certainly not until we are safely indoors again."

Running swiftly through the small park in which they'd chosen to take a few hours' break, he made his way to the main gate. As he'd deduced, their attackers had found a weak spot in the chain-link fence and managed to stumble mindlessly through the resultant gap. He took the same route rather than attempt to open the gates, speeding along until he reached the block of flats where he and Molly had recently taken up residence.

He deposited her gently on the bed, then turned to make his way to the kitchen and some water to clean her wound. Her hand on his wrist stopped him.

He blinked twice in rapid succession before turning to face her.

"You have to do it."

He shook his head in mute denial of her words. No, he didn't _have_ to do anything. Certainly he didn't have to take her knife, slit her throat, watch as she bled out and then decapitate her to keep her from rising up from the dead.

"Please," she said, her voice steady in spite of the faint tremor in her hands. "Please, Sherlock. I don't want to end up like one of them."

He responded with another mute shake of his head. What she was asking...it was sensible. It was merciful. It was a kindness.

It was impossible.

"I can't," he finally managed to say. "I can't just end your life like this, Molly. I can't." He reached out and took her hand, threading his fingers through hers. "You can survive for at least a week before…"

"No." Her voice was firm, her gaze unwavering, but the trembling in her hands was more noticeable now. "I'm not strong enough, Sherlock. I don't want to spend days waiting for the end. And I don't...I can't bear the thought of going through that much pain when it could all be over so much quicker. Can you please do this for me? Please?"

He wanted to say no. He wanted to scream at the uncaring heavens, lay curses on the vampires who'd brought this on them, a moment he'd never ever wanted to face.

But all he did was nod.

Molly smiled, her body slumping in relief as he lifted her into his arms. "You were going to say something to me, in the park," she said, tilting her head up in order to meet his gaze. "Say it now, will you? I've always wanted you to say it first." She gave a small hiccuping laugh as tears began to spill from the corners of her eyes. "Say it like you mean it."

"I- love you," he said with a sad smile. "I love you."

He kissed her, cursing the universe, fate, God, whatever - cursing himself mostly for waiting so long to admit his feelings. He was always too late when it came to sentiment.

"I love you," she replied, removing her hand from her shoulder. The wound was still oozing blood, and her fingers were stained red as she reached for her hunting knife.

"No," he said, pushing the blade away. "Not like that."

When her brow wrinkled in confusion, he reached for the buttons of her blouse and began flicking them open. "One last meal," he said lowly, fingers resting over her pulse-point. "We go out together, Molly Hooper, or not at all."

"Sherlock," she protested, struggling feebly in his arms, trying in vain to push him away. "No! You can't feed from me now, I'm infected, it'll kill you!"

He shrugged. "Yes, that's the idea. And before you start getting all sentimental on me," he rushed on, "let me remind you that the chances of finding an uninfected human in London from which to feed in time to save me from starving to death are vanishingly small." He tenderly stroked her cheek, knowing his actions belied his words even as he spoke them. "So it's only logical that I make the same choice you have: to end my life on my own terms."

She'd stopped struggling as he continued to speak, but her expression was far from happy. Just as well; he didn't need her to be happy, he needed her to be accepting, to make her peace with his decision as she was expecting him to make his peace with hers.

It was only fair.

With a great, shuddering sigh, she finally nodded. "Fine. But don't lie to me, William Sherlock Scott Holmes," she said, trying for stern but only marginally succeeding. The tears welling from her eyes certainly didn't help. "Don't, don't sit there and tell me this is about logic."

He smiled sadly. "You always could see right through me, Molly Hooper." He kissed her again, a last, desperate kiss between never-would-be lovers, laying her gently on the bed and covering his body with his own as the kiss deepened.

When she was gasping for breath he pulled back. "Good-bye, Molly. It's been a rare privilege to know you."

Her smile was wry. "Right back atcha," she replied, a last attempt at humor.

He would hardly chastise her for it now. "I love you."

She closed her eyes. "I love you too."

After one last, lingering look at the woman he loved, he lowered his head, sank his fangs into her throat, and fed.


	3. The Undiscovered Country

Being dead felt an awful lot like being alive.

Sherlock took a moment to process this, to wonder before the haze faded and his habitual mental sharpness returned, if perhaps there was some truth to the idea of an afterlife, discarding it immediately as his awareness of his surroundings came into focus.

The taste of blood in his mouth. The feeling of the mattress beneath his body. The scent of late fall on the cool breeze he felt from the - window? He opened his eyes. Yes, window. The window in Molly's bedroom.

Molly.

He inhaled sharply, taking in the scent of her, allowing himself to process the warm weight in his arms. The warm, breathing _alive_ weight.

 _Molly._

He turned his head enough to see her; sleeping, breathing regularly, heart-rate normal for a sleeping human...so. Not dead.

And if she wasn't dead, then neither was he. His own barely-there respiration (retained solely, he'd long theorized, to allow vampires to actually speak since they could voluntarily stop breathing for extended periods of time) and heart-rate were normal for a somewhat panicky vampire - that is to say, even less perceptible than that of a comatose human.

He was somehow still living - well, unliving if one were to be pedantic - yet not suffering any of the common symptoms of drinking infected human blood. No gut-clenching cramps, no erratic and escalating heartbeat, no shooting pains in the joints…

Not dead. Judging by the pale light streaming through the window shades, it was early morning. They'd returned to the flat in the late afternoon, and it typically took a little more than a half-hour for a vampire to die after ingesting infected blood.

So. Not dead.

He really needed to stop dwelling on that, and try to figure out how it had come to pass.

He eased himself from beneath Molly; she mumbled something semi-coherent and rolled on her side. Her temperature was slightly elevated, but not anywhere close to the fever she should be experiencing at this point; she should be burning up ( _why still alive? he'd drunk her dry, he would swear to it_ ), not merely slightly warm from sleep. Come to think of it, _he_ was slightly warmer than he should be, but vampires didn't get fevers even from drinking infected blood. They just suffered excruciating pain and died.

"Why are we not dead?" he asked aloud, ruffling his hair in frustration. It didn't make sense. There on Molly's throat were the bite marks from his fangs, and on the other side the wound she'd suffered...hang on, two things: the bite marks from his fangs looked nearly healed, not fresh enough even after a night's sleep; and the wound she's suffered when attacked by the zombie was now neatly bandaged.

How had Molly managed that with him sleeping (unconscious?) right next to her? Or was there someone else, had someone entered the flat and decided to help her...no, ridiculous. There were no uninfected humans left in London, he'd swear to that. And the ones who had been left were no Good Samaritans, would more likely have stabbed he and Molly in their sleep than bandage wounds and cover them with - he glanced down - Molly's sheets and quilt.

"Sherlock, go back t'sleep," Molly mumbled, curling closer around herself in the bed. "Promise I'll 'splain it all later. Y'can trust me."

Of course he could trust her; he'd trusted her with his life and his secret after Moriarty had manipulated things so that he had to appear to kill himself ( _good thing that bastard hadn't realized Sherlock was a vampire or things might have gone very differently_ ). He'd trusted her with his heart, even if he'd waited until the verge of death to admit it...dammit, no, he couldn't go back to sleep, not with his mind whirling with a thousand questions!

Molly gave a low groan and rolled on her back, her eyes flickering open reluctantly. "Fine," she groused, as if in response to his agitated thoughts. "We'll do this now." She sat up, plumped the pillows behind her back, and regarded him through steady, somewhat wary, eyes. "You didn't drink enough blood to kill me. And apparently the infection wasn't strong enough to kill you, just knock you out for a few...days."

"Days?" Sherlock's brows shot upward. Surely she was wrong…

But no. She was shaking her head very firmly. "Days, Sherlock. Almost a week, to be exact."

She remained silent while he processed that very unexpected information. "Right," he said after a minute had passed. "Almost a week. So...this is the sixth day? And I'm not dead...but neither are you."

"No, not dead," she agreed, shifting slightly, cutting her eyes to one side for just a brief moment, barely a blink, but impossible for him to miss. "Apparently we're both...getting better." Her lips curled in a genuine smile as she touched her fingers to the edge of her bandage. "I'm not sure if we've found a cure that'll work for more than just us, but it's a start."

Sherlock was missing something, and he _hated_ when he was missing something. His eyes narrowed as he took her in more closely. "Molly," he said after assessing everything about her from the color of her skin (good) to the condition of her hair (surprisingly full and healthy looking, shampoo being somewhat thin in the ground these days). "What did I do?"

He had his suspicions but needed to hear it from her before confirming things with his own eyes.

"You don't remember?" she asked.

He shook his head. She sighed, reached out, and gently took his left arm in her hands. Teeth nipping at her lower lip, she carefully undid the cuff on his sleeve and rolled it back.

"You fed me," she said simply as she traced the line of the new scar on his wrist with her fingertip. "I think you were trying to Turn me, at the last minute."

Turn her. When they both knew how impossible that was. And clearly it hadn't worked since she was still human. Still human, but still alive...his mind raced through the possibilities this new piece of data had opened up, slotting the disparate bits together to see how they fit, to see what made the most sense…

"Once you've eliminated the impossible, whatever remains, however improbable, must be the truth," he murmured when he finally settled on the one, the only, conclusion he could.

Molly nodded, clearly having already worked it out herself. Clever, clever Molly; he'd never appreciated her mind more than he did right now. "Somehow by taking in your newly infected blood, filtering it through my digestive system and then allowing you to drink - but your human digestive system doesn't work that way, it would simply have pooled in your stomach, rather than being fully absorbed the way blood is when a vampire drinks it...hmm, but that appears to be how it's acted on you, so somehow my unconscious attempt to Turn you resulted in some physiological changes, but not enough to actually complete the process, fascinating, a vampire/human hybrid, I wonder what other effects it will have on…"

Molly silenced the excited stream of speculation quite effectively by climbing onto his lap and kissing him. When he'd recovered somewhat from that delightful - and effective - moment of distraction, he pulled back, mindful of the fact that, no matter what other changes his attempt to save her might have wrought, she still had the human need to breathe.

"So," he said tentatively as he gazed into her warm brown eyes, "we might have accidentally stumbled on the cure we've been searching for."

"Yep, that about sums it up," she agreed with a smile. "Kind of makes me wish I'd been bitten sooner!"

He rolled his eyes at the joke - her morbid sense of humor hadn't changed at all.

Good. He'd never want her to change.

"Do you mind if I say it again?" he asked, stroking her hair away from her face.

She didn't bother to ask what he meant, merely held him close, easing them both down so they once again reclined on her bed. "Please do," she said as she turned her face up to meet his. "I have to admit, I love it when you say it first."

"And I love you, Molly Hooper," he replied before capturing her lips in another kiss.

There were things to do, now that they had a potential cure in their - well, blood, rather than hands, but who cared about pedantry at a time like this?

He had much more pleasant things to focus on - like the eager way Molly's hands were exploring his body. Oh wait, she'd stopped - why?

"Do you need, you know," she said, gesturing at her throat. "You were unconscious for a long time, you must be feeling a bit...peckish."

He gave her his most wolfish smile as he rolled her beneath him. "Peckish, yes," he declared. "For blood...no."

His next kiss was designed to leave no doubt in her mind what he meant.

And clever, clever Molly Hooper - _his_ Molly Hooper - needed no further hints.

* * *

 _A/N: Thanks to nocturnias (sherlolly on tumblr) for this inspiration: the zombie infection in his vampiric blood could have created a new Fusion_

 _And thanks to all of my wonderful readers for sticking with me even when I went pretty dark with our beloved OTP. I hope this chapter makes up for all of the angst that came before._


End file.
